What is the average atomic mass for thallium, Tl, if there are two isotopes with the following masses and abundances? Tl-203 has a mass of 203 amu with an abundance of 29.5 % Tl-205 has a mass of 205 amu with an abundance of 70.5 %

A meteor crashes to Earth, is collected and analyzed. To everyone’s surprise, a new element is discovered with an atomic number of 120. Calculate the weight-average atomic mass for this new element, Ubn (Unbinnulium). Show all work below.

A sample of cesium is 75% Cs-133, 20% Cs-132, and 5% Cs-134. What is the average atomic mass?

¹⁰X has a percent abundance of 19.8% and ¹¹X has a percent abundance of 80.2%. What is the average atomic mass of the hypothetical element X?

Element Q is an unknown element. ²⁰Q has abundance of 90.51%, ²¹Q has abundance of 0.21%, and ²²Q has abundance of 9.22%.

Find the average atomic mass of Q and identify the unknown element.

Identify the element with the mass spectra shown below:

What element is represented by the mass spectrum shown below?

Estimate the mass and identify of the element with the given mass spectra shown below.

Which of the following represents isotopes of the element ₂₂⁴⁹Q only?